A new solution for two-bag air suspension system with leaf spring for heavy-duty vehicle

The design problem of a two-bag air suspension system for heavy-duty vehicles is formulated as a two-level (suspension system level and component level) optimization problem. At the suspension system level, optimal stiffness matrix of leaf spring, characteristics of damper and upper rod layout are determined by solving a multi-objective constrained optimization problem with response surface. At the component level, shape and thickness of the leaf spring are formed using cubic-spline curves to make the stiffness matrix as close to the target values cascaded from suspension system level as possible. Simulations using a vehicle model described by multi-body model and FEM of the novel leaf spring validate the suspension system thus derived.     

An Advanced Steering System with Active Kinesthetic Feedback for Handling Qualities Improvement

Advanced Steering System with artificial steering wheel torque-active kinesthetic information feedback for improving handling qualities is discussed. Fundamentally the structure of the system may be considered to another form of model following control. In this system, a driver always remains in the control loop and receives steering control information which give him/her a direct hint to steer a steering wheel. This system works as a stability and control augmentation system of the vehicle to improve the vehicle handling qualities both in compensatory and pursuit control task, and is expected to reduce driver's workload. Effects of this system are analyzed in terms of man-machine system characteristics. Identification of driver dynamics was carried out to find why such improvement could be achieved. Availability of the proposed system is verified by analysis, simulator and proving ground tests.     

Advanced Steering System Adaptable to Lateral Control Task and Driver's Intention

This paper proposes an advanced steering system that adaptively varies the static gain and dynamics of the steering system. The steering system gain is adjusted, depending on whether the driver is in an aggressive or leisurely driving mood. The steering system dynamics is so designed that the command mode of the steering system will be either a rate-command or an attitude-command according to the lateral control task performed by the driver. The recognition system for lateral control tasks, a lane-following or lane-change task is proposed. The findings of simulator tests indicate proposed advanced steering system would remarkably improve the vehicle handling qualities.     

A Review of Four-Wheel Steering Studies from the Viewpoint of Vehicle Dynamics and Control

As the four-wheel steering (4WS) system has great potentials, many researchers' attention was attracted to this technique and active research was made. As a result, passenger cars equipped with 4WS systems were put on the market a few years ago. This report tries to identify the essential elements of the 4WS technology in terms of vehicledynamics and control techniques. Based on the findings of this investigation, the report gives an outline and perspective of the research areas involved.